Device for use in transmitting signals in connection with fire and burglar alarm systems and the like



Nov. 22, 1927. v 1,650,143

. F. T. MATTHEWS DEVICE FOR uss IN TRANSMITTING SIGNALS IN commcnou WITH FIRE AND BURGLAR ALARM SYSTEMS AND THE LIKE Filed Sept. 7. 1927 ATTORNEYS.

Patented Nov. 22,1927.

ram) THOMAS anama,

' nnvron FOR use or BRISBANE, Aus'rRanIA.

IN' 'mmnsivnirrrne 'smnA'Ls In mammals wrrrr FIRE AND BURGLAB ALARIVL sYs'rn'Ms nn THE LIKE.

Application filed September 7, 192'}, Serial No. 218,062, and Australia April 22, 1926.

This invention relates to 'deV-ices'used in transmitting signals, as in' the case of fire alarms and such like. As at; present arranged and wired, it is possible for the alarm device to be operated when certain faultsoccur, in-which case the signal would not be sent through tothe' indicator board,and, further, such fault would not show itself'until the device and line had been tested at-the periodical inspection. The object of this lIlfi vention is: toprovide means whereby the desired signal may be transmitted, and where-' by, except in exceptional circumstances, a

signal is always transmitted, and whereby it is possible to ascertain which line is faulty.

My invention relates more particularly tothe. arrangement of two circuits, one wholly metallic and the othersinetallic and earth.

These circuits could be arranged to operate with any known signal operating device and indicator, but preferably with the signal operating device and indicator hereinafter described and referred to.

In carrying out my invention I provide devices and electric circuits whereby intermittent signals are transmitted from a signal box along wholly metallic and metallic and earth circuits to primary and secondary indicators on the indicator board.

In order that the invention may be better understood I will now describe it with the aid of the accompanying drawings, in which Fig. 1 is a diagram showing one arrangement.

Fig. 2 is a detail showing one modification of a transmitter.

Figures 3, 3 and 3 show respectively cir cuits according to Figure 1 arranged separately in diagrammatic form.

ting signals which I prefer to use, a lever D pivoted on the frame C may be arranged so as tobe operated by the projections A The a lever D is provided with contact springs D DZ'which are thereby caused to make and Fig. 2 shows a transmitter for transmitand leads are provided from the terminals E E and' f-rom the frame C to" the indicator boa-rd in the exchange or fire station, or as the case may be, as will hereinafter be describedf I prefer to arrange the circuits, as shown in Fig. 1, as: follows :-A line K is laid from oneterminal E of the make and break of the alarm device to-one terminalof the main indicator G y at line M is laid from the other terminal E of the'make and break of the alarm device-to one terminal of the secondary indicator G onda'ryindicator G i is' connected to a secon'dary battery NY by line S, the other terminal of which is connected to earth. A. line T,

from the other terminal of the main indicator...Gileads to .a main battery L, the other terminal -of which is connected to a line S Earth circuit NO. 1 '(Fig. 3)From frame C to earth, and thence through battery N, to

indicator G and by line M, to terminal E and by spring contact D to frame C.

Earth circuit N0. 2 (Fig. 3f)From frame C to earth, and thencethrough batteries N and L to indicator G, and by line K to terminal E, and by spring contacts D to frame C. Metallic circuit No. 3 (Fig. 3 -From terminal E by line K, to indicator Gr by line T to battery L and line S to indicator G and thence by line M to terminal E and by spring contacts-D and D to terminal E.

It will be readily seen from the foregoing that, should any fault occur on either of the lines, it will readily show itselfand such line can be cut out by operating the particular fault clearing keys Q Q} Q? until such time as it is possible to rectify the fault. At the same time, it is still possible for an The other terminal of the secalarm to be transmitted on either of the good circuits through either the main or secondary indicators, as the case may be.

The following faults and clearing operations may be given by Way of example Referring to Fig. 1-

1. Short circuit on lines K and M.-Indicators G and G drop and fault is cleared by opening either Q, or Q The call is received through earth and line not broken by fault clearing key operating G or G 2. Short circuit on lines K and M and open circuit on line lVL-The call is received through earth and line K operating indicator G. I

3. Short circuit on lines K and M and open circuit on line K.The call, is received through earth and line M operating indicator G 4. Open circuit on line K.'Ihe call is received through earth and line M operating indicator G 5. Open circuit on line M.The call is received through earth and line K operating indicator G.

6. Earth fault online K.Indicator G I drops and fault is cleared by opening key The call is received through earth and line K operatin indicator G.

It is big ly possible that one of the batteries in the system may fail or go dead and if such occurs the system takes care of this possibility by virtue of the arrangement of the batteries. If one of the batteries fail there will still remain two systems over which the signals may be transmitted.

Having now particularly described and ascertained the nature of my said invention and in What manner the same is to be performed, I declare that What I claim is 2- In a normally open circuit signal system, a. central station having a main indicator and a secondary indicator, a transmitter comprising make and break means normally maintaining said circuit open, a metallic circuit including said transmitter, said indicators and a source of electric supply, a.

In testimony whereof I have signed my name to this specification.

FRED THOMAS MATTHEWS- 

